1. Field of the Invention
The present invention relates to a liquid crystal display that achieves a fast response of a liquid crystal panel.
2. Related Art
FIG. 4 is a block diagram of a circuit that executes the correction for a fast response of a conventional liquid crystal display.
In FIG. 4, 1 signifies an image memory that stores input image data, 2 a synchronization control circuit that receives the image data, and delivers the image data and a synchronization control signal, 3 a look-up table formed on a ROM, which stores correction data in correspondence with the inputs of current image data outputted from the synchronization control circuit 2 and previous image data outputted from the image memory 1. 4 signifies a source-line drive circuit that outputs a drive signal based on the output from the look-up table 3 and the control signal from the synchronization control circuit 2 to source lines, 5 a gate-line drive circuit that outputs a drive signal based on the control signal outputted from the synchronization control circuit 2 to gate lines. 6 signifies a liquid crystal panel that forms a display in accordance with the image data, by the output from the gate-line drive circuit 5 and the output from the source-line drive circuit 4.
The conventional method of achieving a fast response of a liquid crystal panel includes storing the input digital image data for one frame in the image memory 1, storing the correction data determined by the two inputs of the input digital image data and the image data with one frame delayed, read from the image memory 1, in the look-up table 3, converting the image data into emphasized correction data by the look-up table 3, and driving the liquid crystal panel 6 by using this correction data, thereby enhancing the response speed of a transmittance change, namely, gradation change of the liquid crystal panel 6.
The conventional method of achieving a fast response of a liquid crystal panel executes a data conversion by the look-up table 3, on the basis of the two input data of current and previous image data, and thereby enhances the response speed. However, this conventional method only executes the correction by the image data; and even if the frame rate or the ambient temperature varies, if the image data are the same, the correction value will always be constant. Therefore, the conventional method is impossible of a correction in accordance with the environmental conditions in use (frame rate, ambient temperature, etc.).
The invention has been made in view of the foregoing circumstances, and it is an object of the invention to provide a liquid crystal display that enables a correction in response to the environmental conditions in use, and enhances a response speed of a liquid crystal panel.
According to one aspect of the invention, a liquid crystal display includes: a frame rate detection unit that detects a frame rate of a current image data; a correction data generation unit receiving the current image data and a previous image data inputted one frame before, having a plurality of look-up tables, each of which is configured in such a manner that when the current image data is greater than the previous image data, it outputs a correction data greater than the current image data, and when the current image data is smaller than the previous image data, it outputs a correction data smaller than the current image data; and a drive circuit that drives a liquid crystal panel with an output from the correction data generation unit. In this construction, one of the plural look-up tables of the correction data generation unit is selected in accordance with the frame rate of the current image data detected by the frame rate detection unit.
According to another aspect of the invention, a liquid crystal display includes: a frame rate conversion unit that converts a frame rate of a current image data into a specific frame rate to output it as a converted image data; a correction data generation unit receiving the converted image data outputted from the frame rate conversion unit and a previous converted image data inputted one frame before, which is configured in such a manner that when the converted image data is greater than the previous converted image data, it outputs a correction data greater than the converted image data, and when the converted image data is smaller than the previous converted image data, it outputs a correction data smaller than the converted image data; and a drive circuit that drives a liquid crystal panel with an output from the correction data generation unit.
According to another aspect of the invention, a liquid crystal display includes: an ambient temperature detection unit that detects an ambient temperature; a frame rate conversion unit that converts a frame rate of a current image data into a frame rate corresponding to the ambient temperature detected by the ambient temperature detection unit to output it as a converted image data; a correction data generation unit receiving the converted image data outputted from the frame rate conversion unit and a previous converted image data inputted one frame before, which is configured in such a manner that when the converted image data is greater than the previous converted image data, it outputs a correction data greater than the converted image data, and when the converted image data is smaller than the previous converted image data, it outputs a correction data smaller than the converted image data; and a drive circuit that drives a liquid crystal panel with an output from the correction data generation unit.
According to another aspect of the invention, the liquid crystal display further includes: a synchronization control circuit receiving the current image data, outputting a control signal to the drive circuit; and an image memory controlled by the synchronization control circuit, storing the current image data, in which the previous image data one frame before is outputted from the image memory.
According to another aspect of the invention, the liquid crystal display further includes: a synchronization control circuit receiving the converted image data, outputting a control signal to the drive circuit; and an image memory controlled by the synchronization control circuit, storing the converted image data, in which the previous converted image data one frame before is outputted from the image memory.
And, preferably, the correction data generation unit is formed on a non-volatile semiconductor memory.
The invention being thus constructed, its displays the following effects.
The liquid crystal display of the invention is provided with: a frame rate detection unit that detects a frame rate of a current image data; a correction data generation unit receiving the current image data and a previous image data inputted one frame before, having a plurality of look-up tables, each of which is configured in such a manner that when the current image data is greater than the previous image data, it outputs a correction data greater than the current image data, and when the current image data is smaller than the previous image data, it outputs a correction data smaller than the current image data; and a drive circuit that drives a liquid crystal panel with an output from the correction data generation unit, in which one of the plural look-up tables of the correction data generation unit is selected in accordance with the frame rate of the current image data detected by the frame rate detection unit. Thereby, the invention executes a correction in accordance with the frame rate of the current image data, and achieves a fast response in a change of the gradation.
Further, the liquid crystal display of the invention is provided with: a frame rate conversion unit that converts a frame rate of a current image data into a specific frame rate to output it as a converted image data; a correction data generation unit receiving the converted image data outputted from the frame rate conversion unit and a previous converted image data inputted one frame before, which is configured in such a manner that when the converted image data is greater than the previous converted image data, it outputs a correction data greater than the converted image data, and when the converted image data is smaller than the previous converted image data, it outputs a correction data smaller than the converted image data; and a drive circuit that drives a liquid crystal panel with an output from the correction data generation unit. Thereby, the invention attains a suitable correction even in a change of the frame rate of the current image data, and achieves a fast response in a change of the gradation.
Further, the liquid crystal display of the invention is provided with: an ambient temperature detection unit that detects an ambient temperature; a frame rate conversion unit that converts a frame rate of a current image data into a frame rate corresponding to the ambient temperature detected by the ambient temperature detection unit to output it as a converted image data; a correction data generation unit receiving the converted image data outputted from the frame rate conversion unit and a previous converted image data inputted one frame before, which is configured in such a manner that when the converted image data is greater than the previous converted image data, it outputs a correction data greater than the converted image data, and when the converted image data is smaller than the previous converted image data, it outputs a correction data smaller than the converted image data; and a drive circuit that drives a liquid crystal panel with an output from the correction data generation unit. Thereby, the invention executes a correction in accordance with the ambient temperature, and achieves a fast response in a change of the gradation.
Further, the liquid crystal display of the invention is further provided with: a synchronization control circuit receiving the current image data, outputting a control signal to the drive circuit; and an image memory controlled by the synchronization control circuit, storing the current image data, in which the previous image data one frame before is outputted from the image memory, whereby the previous image data can be formed.
Further, the liquid crystal display of the invention is further provided with: a synchronization control circuit receiving the converted image data, outputting a control signal to the drive circuit; and an image memory controlled by the synchronization control circuit, storing the converted image data, in which the previous converted image data one frame before is outputted from the image memory, whereby the previous converted image data can be formed.
Further, since the correction data generation unit is formed on a non-volatile semiconductor memory, the circuit size can be reduced.